Polyembryony, Biology

Assignment Help:

Polyembryony

Presence of more than one embryo in a seed is termed polyembryony. The phenomenon, first discovered in orange seeds by Leeuwenhoek (1719), attracted considerable attention because of its potential for application in and horticulture. Polyembryony is broadly classified into simple and multiple, depending on whether the supernumerary arises in one or more embryo sacs in the ovule. Simple polyembryony may be sexual or asexual. In sexual polyembryony embryos may originate from the fertilized egg and synergids, or by budding or cleavage of the polyembryony cells or suspensor of the zygotic embryo.

Asexual embryos are produced within the embryo sac without fertilization. Embryos may also originate from diploid nucellar or integumentary cells of the ode and grow into the embryo sac. These embryos are termed adventive or sporophytic. Multiple polyembryonies involve production of accessory embryos from two or more embryo sacs in the same ovule. For example, in the sea Island cotton, Gossypium barbadense, fertilization of egg in one embryo sac stimulates the induction of embryo from an unfertilized egg in the adjacent embryo sac within the same ovule. Thus, diploid-haploid twin embryos are produced in the seed.


Related Discussions:- Polyembryony

What is rhizopus - fungi, What is Rhizopus - Fungi? Rhizopus is a commo...

What is Rhizopus - Fungi? Rhizopus is a common laboratory contaminant. It is a spoiling mould and found frequently on the surface of bread, fruits and vegetables. It can grow a

Explain components of second heart sounds, Explain Components of second hea...

Explain Components of second heart sounds? The first component of S 2 is due to closure of aortic valve (A,). The second component is due to closure of pulmonary valve (P 2 ).

Explain procedure for performing the completed coliform test, Explain Proce...

Explain Procedure for Performing the Completed Coliform Test? Completed test is the last step in the Coliform test procedure which is described herewith. Conduct the exercise f

Biological energy, Biological energy: Whenever matter is broken down its c...

Biological energy: Whenever matter is broken down its chemical energy is released as heat. Non biological system can utilize this heat energy directly in the performance  of work,

What are the three major types of rna, Q. What are the three major types of...

Q. What are the three major types of RNA? What is meant by heterogeneous RNA? Messenger RNA, or mRNA, transfer RNA, or tRNA, and ribosomal RNA, or rRNA, are the three main type

Aortic stenosis, Aortic Stenosis   Aortic stenosis is due to an obstruc...

Aortic Stenosis   Aortic stenosis is due to an obstructive lesion that interferes with the blood flow out of the left ventricle. Depending upon the site of obstruction to the o

Assessment of wilm tumour, Assessment   The child with wilm's tumour wi...

Assessment   The child with wilm's tumour will present you with a large mass in the loin or an enlarging abdomen. This mass may be noticed accidently by  the parent of  the chi

Financing of healthcare - Principles, Normal 0 false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Causes of gerd, In addition, pregnancy or constipation may worsen GERD by i...

In addition, pregnancy or constipation may worsen GERD by increasing intra-abdominal pressure. Secondary causes of GERD include reflux caused by acid hypersecretory states, connec

Clinical evaluation of infants and young children, Clinical Evaluation of I...

Clinical Evaluation of Infants and Young Children Approaches to clinical practice advanced in recent year are mostly directed at older children and adolescents. There has not b

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd